It's mostly to do with archtypes. Kingdra can bench attack any delta (Eggy/Raichu/Draggy/Gyara/etc), 1HKO's Dark Steelix/EX, as well as a few other things. If you do decent amounts of bench damage to something with Kingdra (hopefully with 3+ energies on it), then you can devo flash it with Espeon for a knock out. Without any trainer cards in play, Espeon OHKO's Medicham EX, Lugia EX, Gardevoir delta, and a number of other pokemon. It can also hit anything on the bench for 30. If your opponent has a stadium in play, then Espeon does 90. If theres an energy root/curse powder attached to something as well, 120. Flareon EX is another fire tech incase you have no Kingdra out, and the burn/confuse effect is very useful as well. Cargo doesn't really have a strategy.